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We study the spin-dependent transport properties of a spin valve based on a double quantum dot. Each quantum dot is assumed to be strongly coupled to its own ferromagnetic lead, while the coupling between the dots is relatively weak. The…

Mesoscale and Nanoscale Physics · Physics 2021-07-21 Patrycja Tulewicz , Kacper Wrzesniewski , Szabolcs Csonka , Ireneusz Weymann

A correct general formula for the spin current through an interacting quantum dot coupled to ferromagnetic leads with magnetization at an arbitrary angle $\theta$ is derived within the framework of the Keldysh formalism. Under asymmetric…

Mesoscale and Nanoscale Physics · Physics 2009-03-18 Hao Zhang , Guang-Ming Zhang , Lu Yu

Current-voltage characteristics of a spintromechanical device, in which spin-polarized electrons tunnel between magnetic leads with anti-parallel magnetization through a single level movable quantum dot, are calculated. New exchange- and…

Mesoscale and Nanoscale Physics · Physics 2020-05-20 Olya A. Ilinskaya , Danko Radic , Hee Chul Park , Ilya V. Krive , Robert I. Shekhter , Mats Jonson

We investigate spin-polarized transport phenomena through double quantum dots coupled to ferromagnetic leads in series. By means of the slave-boson mean-field approximation, we calculate the conductance in the Kondo regime for two different…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 Yoichi Tanaka , Norio Kawakami

We investigate the spin dynamics of a quantum dot with a spin-1/2 ground state in the Coulomb blockade regime and in the presence of a magnetic rf field leading to electron spin resonances (ESR). We show that by coupling the dot to leads,…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Hans-Andreas Engel , Daniel Loss

Te is a naturally p-doped semiconductor with a chiral structure, where an electrical current causes the conduction electrons to become spin polarized parallel to the transport direction. In this paper, we present a comprehensive theoretical…

Mesoscale and Nanoscale Physics · Physics 2024-03-05 Reena Gupta , Andrea Droghetti

We analyze cotunneling transport through two quantum dots in series weakly coupled to external ferromagnetic leads. In the Coulomb blockade regime the electric current flows due to third-order tunneling, while the second-order…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 I. Weymann

We develop a theory for spin transport and magnetization dynamics in a quantum-dot spin valve, i.e., two magnetic reservoirs coupled to a quantum dot. Our theory is able to take into account effects of strong correlations. We demonstrate…

Mesoscale and Nanoscale Physics · Physics 2018-01-09 N. M. Gergs , S. A. Bender , R. A. Duine , D. Schuricht

We report measurements of spin transitions for GaAs quantum dots in the Coulomb blockade regime, and compare ground and excited state transport spectroscopy to direct measurements of the spin polarization of emitted current. Transport…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 R. M. Potok , J. A. Folk , C. M. Marcus , V. Umansky , M. Hanson , A. C. Gossard

In this paper, spin-dependent transport through a spin diode composed of a quantum dot coupled to a normal metal and a ferromagnetic lead is studied. The current polarization and the spin accumulation are analyzed using the equations of…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 M. Bagheri Tagani , H. Rahimpour Soleimani

We investigate the noise in spin transport through a single quantum dot (QD) tunnel coupled to ferromagnetic electrodes with noncollinear magnetizations. Based on a spin-resolved quantum master equation, auto- and cross-correlations of…

Mesoscale and Nanoscale Physics · Physics 2024-03-14 Guanjian Hu , Shikuan Wang , Jing Hu , RuiQiang Li , Yiying Yan , JunYan Luo

We present studies of the Coulomb blockade and Kondo regimes of transport through a quantum dot connected to current leads through spin-polarizing quantum point contacts (QPCs). This structure, arising from the effect of lateral spin-orbit…

Strongly Correlated Electrons · Physics 2010-12-21 Anh T. Ngo , Edson Vernek , Sergio E. Ulloa

We have studied the current through a carbon nanotube quantum dot with one ferromagnetic and one normal-metal lead. For the values of gate voltage at which the normal lead is resonant with the single available non-degenerate energy level on…

Mesoscale and Nanoscale Physics · Physics 2008-08-20 Christopher A. Merchant , Nina Markovic

We discuss the possibility to generate, manipulate, and probe single spins in single-level quantum dots coupled to ferromagnetic leads. The spin-polarized currents flowing between dot and leads lead to a non-equilibrium spin accumulation,…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Matthias Braun , Jürgen König , Jan Martinek

We in this paper study theoretically the spin-polarized quantum transport through a T-shape quantum dot-array by means of transfer-matrix method along with the Green^{,}s function technique. Multi-magnetic fields are used to produce the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Rui Wang , J. -Q. Liang

We study ballistic transport through semiconductor quantum point contact systems under different confinement geometries and applied fields. In particular, we investigate how the {\em lateral} spin-orbit coupling, introduced by asymmetric…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Anh T. Ngo , P. Debray , Sergio Ulloa

Motivated by the experimental evidence of the Nagaoka ferromagnetism in quantum dot systems by Dehollain et al [1], we search for possible confirmation of such kind of ferromagnetism by analyzing the spin-resolved transport properties of a…

Mesoscale and Nanoscale Physics · Physics 2024-10-04 Piotr Trocha , Emil Siuda , Ireneusz Weymann

In a nanomagnet (whose total spin S< 1000), very small polarized currents can lead to magnetic reversal. Treating on the same footing the transport and magnetic properties of a nanomagnet connected to magnetic leads via tunneling barriers,…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 X. Waintal , O. Parcollet

The tunnel current and magnetoresistance (TMR) are investigated in magnetic tunnel junctions consisting of a spin-filter tunnel barrier, sandwiched between a ferromagnetic (FM) electrode and a nonmagnetic (NM) electrode. The investigations…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Alireza Saffarzadeh

An unpolarized charge current passing through a chaotic quantum dot with spin-orbit coupling can produce a spin polarized exit current without magnetic fields or ferromagnets. We use random matrix theory to estimate the typical spin…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Jacob J. Krich , Bertrand I. Halperin